Electrical circuits for gas-discharge tubes



R. S. TOUR Aug. 4, 1936.

ELECTRICAL CIRCUITS FOR GAS DISCHARGE TUBES Filed Sept. 7, 1953 2 Sheets-Sheet 1 WWW H J0 lam Jl ll 3/ 1L II 32.

1936- R. s. TOUR 2,050,135

ELECTRICAL CIRCUITS FOR GAS DISCHARGE TUBES Filed Sept. 7, 1935 2 Sheets-Sheet 2 W W [Md Y Patented Aug. 4, 1936 ELECTRICAL cmcm'rs roa GAS-DISCHARGE mas Reuben 8. Tour, Cincinnati, Ohio Application September 7, 1933, Serial No. 688,471

13 Claims.

My invention relates to an improved combination of electrical circuits for a plurality of gaseous-discharge tubes, where a continuous parallel, or predetermined sequential intermittent discharge of selected tubes is desired.

The principal object of the present invention is to make possible the selective operation, continuously or intermittently in predetermined sequence, of any or several of a plurality of gasenus-discharge tubes, connected in parallel to a single source of power supply, said tubes serving for illumination, for advertising, or for operation of electrical relays or similar devices.

Other objects of my invention will appear from the detailed descriptions of specific applications hereinafter contained.

The present art of using gaseous-discharge tubes normally requires that each tube be connected across an individual source of power which must necessarily be of sufllciently high voltage to break down, discharge, or ionize the gas in the tube although such voltage is much higher than is necessary to maintain current flow through the tube when once the tube has been discharged.

The voltage characteristic of gaseous discharge tubes, which requires high voltage for breakdown or starting followed by a much lower voltage a for maintaining current flow, makes impractical under existing systems, the parallel operation of 80 a plurality of tubes on one source of power. Ex-

cept by the use of expensive auxiliary apparatus, the discharge of one tube immediately reduces the applied voltage on the others; or if a constant voltage transformer is used, the discharged tubes will be much overloaded. This voltage characteristic of gaseous discharge tubes not only requires individual sources of power for each tube in operation, but requires further that these sources have current limiting properties.

Gaseous-discharge tubes may be ionized or discharged by applying across them a voltage surge or an alternating voltage of steep wave front such as is characteristic of high frequency alternating potentials. Once discharged by such high frequency wave front, the tubes may be supplied current from someother suitable power source of proper voltage for the discharged tubes.

The high frequency alternating potentials or voltage surges with steep wave fronts may originate from any suitable source, the power required being negligible. A sparking device as is shown in these specifications is ordinarily the most simple and effective source of voltage surges, but is not necessarily the only possible source.

55 Since the energy required in the high frequency circuits is exceedingly small and since the power carried through the tube may be comparatively large, this method of operating gaseous discharge tubes lends itself admirably to the motivation of electrical relays or similar devices. Thus, if B a spark of negligible energy be caused to occur in the high frequency circuit of any chosen tube, that tube is ionized and can pass a large current through any series connected relay solenoid. In this way a series of relays or a multiple point 10 relay may be operated in any specified sequence. Or, if desired, the spark or other high frequency source may be maintained in continuous operation external to the respective high frequency circuits of any of the tubes, connection being 15 made to impress the continuously available train of voltage surges across any desired tube or tubes at any desired time, thus operating the relay or other device. Both the above systems are shown for relay omration in the drawings, 20 wherein:

Figure 1 is a diagram of the new system of circuits as employed for the operation of an on-and-off relay, using one gaseous discharge tube for the on" position and another for the 25 off" position.

Figure 2 is a diagram of the new system of circuits as employed for the operation of a multiple point relay or other device requiring the use of a plurality of gaseous-discharge tubes and depend- 30 ing on the selective discharge of one or several of said tubes.

Figure 3 is a diagram of the new system of circuits as simplified for operating a plurality of gaseous-discharge tubes in an illuminated sign, 35 where the sequence of operation of the respective tubes may be predetermined.

Figure 4 is a modification of Figure 3.

Figure 5 is a diagram of the new system of circuits as further simplified and applied broadly 4 to the continuous operation of gaseous-discharge tubes in parallel.

Referring to Figure 1, the numerals l and 2 indicate gaseous-discharge tubes each series-connected with one of the relay coils 3 and 4 of an a on-and-ofl relay. The series couplets of tube and coil are connected in parallel across coil 5 of a transformer energized by line circuit 6. The potential of transformer 5 is insuflicient to discharge tubes I or 2, but if an ionizing voltage "surge be imposed across either tube, its resistance will then be so lowered as to permit current to flow from transformer 5 through that tube and its relay coil 3 or 4, which respectively operate external circut controlling devices, not shown.

The voltage surges necessary for ionizing tubes i and 2 are respectively available from spark gaps 1-9 or 8-9, sparking terminals I and 8 being supplied high potential by transformer I 0 to which they are connected in parallel through separating chokes II and I2. Transformer III is energized by any commercial or low frequency source of power and supplies high potential to terminals I and 8 respectively through controlling switches I3 and I4, and condensers I5 and IS,

the latter serving to limit the energy in the spark and prevent destructive arcing. The return circuit for the high potential spark discharge from common sparking terminal 9, which is preferably the needle of a galvanometer, adapted as described in my Patent No. 1,962,849, of June 12, 1934; is connected to the-common terminal of tubes I and 2 by means of a wire I5 in the meter, and external leads. A spark discharge at 1 or 8 sets up also a high frequency voltage surge which is imposed across tubes I or 2 respectively through condensers II or I8, which also serve as charging condensers across high potential winding I 0. The connections of condensers I! and I8 to the tubes are separated by relay coils 3 and 4 now acting as chokes to permit building up of a surge potential across the individual tubes. Tube I is thus in a. high frequency circuit through I1, I3, I5 with terminal I which sparks when desired to terminal 9 connected to the other side of the tube through wire I1. Likewise tube 2 is in a high frequency circuit through I8, I4, I6 with terminal 8.which sparks to terminal 9 when desired, and wire 11.

The switches I3 and I4 may be manually or mechanically controlled by any suitable means or may be operated by the relay solenoid coils 3 and 4 in alternating sequence. For such operation the switch arms are mechanically connected together by means of a link I6, so that when solenoid 3, for instance, is energized to open switch I3, switch I4 is automatically closed and ready so that a high frequency circuit will be completed through tube 2 by movement of the galvanometer needle 9 into sparking relation with spark terminal 8. When such spark occurs the solenoid 4 is energized by the low potential circuit from transformer 5 through tube 2 which is ionized by the generated high frequency at the spark gap. The arm of switch I4 is accordingly moved to open the circuit of terminal 8 and close that of terminal "I for actuation on the reverse movement of the needle 9.

In Figure 2 the new system of circuits has been shown expanded and adapted for theoperation of a plurality of gaseous discharge tubes 20, 2|, 22, and 23 serving to operate a multiple point relay or other similar device. Each of said tubes is series connected, with one of the solenoid coils 24, 25, 26, 21 of the relay, the couplets of tube and coil so formed being connected in parallel across the low potential, low frequency transformer 28, energized by line circuit 29. The gas tubes, exclusive of their series coils, are respectively connected by condensers 30, 3I, 32, 33 into individual high frequency circuits. The said high frequency circuits are in turn connected in parallel through switches 34, 35, 36, 31 to one terminal of a high frequency source, such as spark gap 38, the other terminal of which is connected to the common terminals of the tubes. The high frequency circuits are supplied high potential low frequency current for sparking across gap 38 by transformer coil 39 through choke coils 40, 4|, 42 and 43, with condensers 39, 3|, 32, and 33 serving as charging condensers. A condenser 44 may be used if necessary as a current limiting impedance to prevent destructive arcing at gap 38. The controlled operation of the switches 34, 35, 36 and 31 ionizes the respective tubes permitting the flow of low potential current through the respective series connected relay coils 24, 25, 26 and 21 whereby the relay is operated.

In Figure 3 the new system of. circuits as shown in the above figures is simplified for use in illuminated sign advertising, while Figure 4 is a modification of Figure 3. In Figures 3 and 4, a plurality of gaseous-discharge tubes 45, 46, 41 and 48 are connected in parallel across the transformer coil 49, high frequency chokes 50, 5|, 52 and 53 being inserted, one to a tube, into one connecting lead of each tube. High potential low frequency transformer 54 charges condenser 55 andsupplies energy to the sparking device 56 through the optional current limiting impedance 51, the latter to prevent destructive arcing. The high frequency generated by the spark surges is directed by switches 58, 59, 69, 6| respectively to gaseous-discharge tubes 45, 46,41 and 48, while choke 62 prevents sparking at the switch points.

In Figure 5 the new system of circuits is furo ther simplified for use in the continuous and simultaneous operation of a plurality of gaseousdischarge tubes 63, 64, 65 and 66 connected in,

parallel across a low potential transformer coil 61. The high potential low frequency circuit of transformer coil 68 charges condenser 69 and supplies energy to the spark 10 through current limiting impedance 1 I. The high frequency surges from the sparking at III are imposed across tubes 63, 64, 65 and 66 being constrained by choke I2 from shorting around the tubes. The said tubes are therefore kept in a state of apparently continuous illumination or discharge by the alternating low potential current supplied from transformer coil 61.

Having thus fully described my invention what I claim as new and desire to secure by Letters Patent is:

1. A system of electrical circuits for the simultaneous discharge of a plurality of cold cathode gaseous-discharge tubes, said system comprising a plurality of said tubes connected in parallel across a power source of lower potential then required to ionize the said tubes, a high frequency choke series connected between said plurality of tubes and said low potential source, a high frequency power source, and means for continuously impressing said high frequency across the electrodes of said gaseous-discharge tubes whereby said tubes are ionized on each half cycle of alternating potential and their resistance so lowcred as to permit completion of the low potential circuit through said tubes.

2. A system of electrical circuits for the simultaneous discharge of a plurality of cold cathode gaseous-discharge tubes, said system comprising a plurality of said tubes connected in parallel across a power source of lower potential than required to ionize the said tubes, a high frequency choke series connected between said plurality of tubes and said low potential source, a high potential circuit, a sparking device in said high potential circuit for generating high frequency oscillations, and circuits for continuously impressing said oscillations across the electrodes aosonss of said gaseous-discharge tubes whereby said tubes are ionized on each half cycle of alternating potential and their resistance so lowered as to permit completion oi the low potential circuit through said tubes.

3. A system of electrical circuits for the selective discharge of a predetermined tube or tubes among a plurality of cold cathode gaseous-discharge tubes, said system comprising a plurality of said tubes. a like plurality of choke coils each series connectkd with one of said tubes to form a couplet, the plurality'of couplets so formed being connected in parallel across a power source of lower potential-than required to ionize the tubes, a power source to supply high frequency oscillations, choke coils to prevent shunting the high frequency oscillations around the tubes, condensers for coupling the high frequency oscillations to the respective tubes, and circuits for selectively and continuously impressing said high frequency oscillations across the electrodes of predetermined gaseous-discharge tubes whereby said tubes are ionized on each half cycle of alternating potential and their resistance so lowered as to permit completion of the low potential circuit through the selected tubes and the connected coils,

4. A system of electrical circuits for the selective discharge of a predetermined tube or tubes among a plurality of cold cathode gaseous-discharge tubes. said system comprising a plurality of said tubes, a like plurality of choke coils each series connected with one of said tubes to form a couplet, the plurality of couplets so formed being connected in parallel across a power source of lower potential than required to ionize the tubes, a plurality of high frequency circuits for impressing ionizing oscillations across the electrodes of said tubes, one of said tubes exclusive of its choke coil being connected in series in each of said high frequency circuits, a power source to supply high frequency oscillations choke coils to prevent shunting the high frequency surges around the tubes and means for selectively and continuously transmitting said high frequency oscillations to predetermined high frequency circuits to ionize and so lower the resistance of their respectively included gaseous-discharge tubes as to permit completion of the low potential circuit through the selected tubes and the connected coils.

5. A system of electrical circuits for the selective discharge of a predetermined tube or tubes among a plurality of cold cathode gaseous-discharge tubes, said system comprising a plurality of said tubes, a like plurality of choke coils each series connected with one of said tubes to form a couplet, the plurality of couplets so formed being connected in parallel across a power sourceof lower potential than required to ionize the tubes, a plurality of high frequency circuits for impressing ionizing oscillations across the electrodes of said tubes, one of said tubes exclusive of its choke coil being connected in series in each of said high frequency circuits, a power source to supply high frequency oscillations, choke coils to prevent shunting the high frequency oscillations around the tubes, condensers for coupling the high frequency oscillations to the respective tubes, and means for selectively and continuously transmitting said high frequency oscillations to predetermined high frequency circuits to ionize and so lower the resistance of their respectively included gaseous-discharge tubes as to permit completion of the low potential circuit through the selected tubes and the connected coils.

6. A system of electrical circuits for the selective discharge of a predetermined tube or tubes among a plurality of cold-cathode gaseous-discharge tubes, said system comprising a plurality of said tubes, a like plurality of choke coils each series connected with one of said tubes to form 5 a couplet, the plurality of couplets so formed being connected-in. parallel across a power source of lower potential than required to ionize the tubes, a high potential circuit, a sparking device in said high potential circuit for generating high frequency oscillations, and circuits for selectively and continuously impressing said high frequency oscillations across the electrodes of predetermined gaseous-discharge tubes whereby said tubes are ionized and their resistance so lowered as to 15 permit completion of the low potential circuit through the selected tubes and the connected coils.

7. A system of electrical circuits for the selective discharge of a predetermined tube or tubes 20 among a plurality of cold cathode gaseous-discharge tubes, said system comprising a plurality of said tubes, a like plurality of choke coils each series connected with one of said tubes to form a couplet, the plurality of couplets so formed be- 25 ing connected in parallel across a power source of lower potential than required to ionize the tubes, a high potential circuit, a sparking device in said high potential circuit for generating high frequency oscillations, choke coils to prevent shunting the high frequency oscillations around the tubes, condensers for coupling the high frequency oscillations to the respective tubes, and circuits for selectively and continuously impress-' ing said high frequency oscillations across the electrodes of predetermined gaseous-discharge tubes whereby said tubes are ionized and their resistance so lowered as to permit completion of the low potential circuit through the selected tubes and the connected coils.

8. A system of electrical circuits for the selec-, tive discharge of a predetermined tube or tubes among a plurality of cold cathode gaseous-discharge tubes, said system comprising a plurality of said tubes, a like plurality of choke coils each series connected with one of said tubes to form a couplet, the plurality of couplets so formed being connected in parallel across a power source of lower potential than required to ionize the tubes, a plurality of high frequency circuits for impressing ionizing oscillations across said tubes, one of said tubes exclusive-of its choke coil being connected in series in each of said high frequency circuits, a high potential circuit, a sparking device in said high potential circuit for generating high frequency oscillations, choke coils to prevent shunting the high frequency oscillations around the tubes, condensers for coupling the high frequency oscillations to the respective tubes, and means for selectively and continuously 60 transmitting said high frequency oscillations to predetermined high frequency circuits to ionize and so lower the resistance of their respectively included gaseous-discharge tubes as to permit the completion of the low potential circuit 65 thflough the selected tubes and the connected co s.

9. A system of electrical circuits for the selective discharge of a predetermined tube or tubes among a plurality of cold cathode gaseous-dis- 70 charge tubes, said system comprising a plurality of said tubes, a like plurality of choke coils each series connected with one of said tubes to form a couplet, the plurality of couplets so formed, being connected in parallel across a power source of lower potential than required to ionize the tubes, a plurality of high frequency circuits for impressing ionizing oscillations across said tubes, one of said tubes exclusive of its choke coil being connected in series in each of said high frequency circuits, a high potential circuit to supply energy to the said high frequency circuits, a sparking device for generating high frequency oscillations and a switch in each of said high frequency circuits, choke coils to prevent shunting the high frequency oscillations around the tubes, condensers for coupling said high frequency oscillations to the respective tubes, and means for selectively operating said switches to cause sparking and continuous high frequency oscillations in predetermined high frequency circuits to ionize and so lower the resistance of their respectively included gaseous-discharge tubes as to permit completion of the low potential circuit through the selected tubes and the connected coils.

10. A system for selectively operating a plurality of solenoid coils, comprising in combination with said coils a like plurality of gaseous-discharge tubes, each of said tubes being series connected with one of said coils and the couplets so formed being connected in parallel in a circuit of lower potential than required to ionize said tubes, and means for the selective discharge of predetermined tubes among said plurality of gaseous-discharge tubes thus completing the low potential circuit through the selected tubes and the connected coils.

11. A system for selectively operating a plurality of solenoid coils, comprising in combination with said coils a like plurality of gaseousdischarge tubes, each of said tubgs being series connected With one of said coils and the couplets so formed being connected in parallel in a circuit of lower potential than required to ionize said tubes, a plurality of high frequency circuits for impressing ionizing surges across said tubes, one

of said tubes exclusive of its relay coil being se-' ries connected, in each of said high frequency circuits, and means for selectively supplying high frequency surges to predetermined high frequency circuits to ionize and so lower the resistance of the respectively included tubes as to permit completion of the low potential circuit through the selected tubes and the connected solenoid coils.

12. A system for selectively operating a plurality of solenoid coils, comprising in combina- 5 tion with said coils a like plurality of gaseousdischarge tubes, each of said tubes being series connected with one of said coils and the conplets .so formed being connected in parallel in a circuit of lower potential than required to ionize said tubes, a plurality of high frequency circuits for impressing ionizing surges across said tubes, a plurality of condensers, one of said tubes being in serieswith one of said condensers in each of said high frequency circuits, a high potential cir- 1 cuit, a sparking device in said high potential circuit for generating high frequency surges, and means for selectively transmitting the high frequency surges to predetermined high frequency circuits to ionize and so lower the resistance of the respectively included tubes as topermit completion of the low potential circuit through the selected tubes and the connected solenoid coils. 13. A system for selectively operating a plurality of solenoid coils, comprising in combination with said coils a like plurality of gaseous-discharge tubes, each of said tubes being series connected with one of said coils and the couplets so formed being connected in parallel in a circuit of lower potential than required to ionize said tubes, a plurality of high frequency circuits for impressing ionizing surges across said tubes, a plurality of condensers, one of said tubes being in series with one of said condensers ineach of said high frequency circuits, a high potential REUBEN s. TOUR, 

